Rotary pumps of the type described above are not new per se. For example, U.S. Pat. No. 2,011,451 discloses a pump utilizing helical wire compression springs acting on each vane which have a generally radially extending axis. This known rotary pump has certain disadvantages and drawbacks. For example, it has been found that the springs for each vane adjacent each other in the axial direction exert a non-uniform pressure against the bore of the housing, that is, angularly as a result of normal, unavoidable production tolerances in the spring support surfaces. Additionally, it is noted that the springs consume a relatively large amount of space in the radial direction which produces an unfavorable reduction in the associated pump space for housing the springs. Additionally, the springs of the known rotary pump are difficult to install and insert in recesses or pockets in the vane.